This application requests funds for a new training program at the Chemistry/Biology Interface at Yale University. Over the past five years Yale has made a conscious effort to increase its representation in this area through new hires and promotions at the junior and senior levels in the departments of Molecular, Cellular and Developmental Biology, Chemistry, Pharmacology and Molecular Biophysics and Biochemistry (MB&B). This expansion has dramatically enhanced our ability to train students in this exceedingly important research area. Taken with the current strengths in synthetic and mechanistic chemistry and in molecular biology and biochemistry for which Yale is distinguished, these new appointments create an environment for interfacial training that is unlike anything Yale has experienced in decades. The Yale Chemical Biology Program involves 25 trainers from five departments. Support is sought for 12 predoctoral trainees. All trainees admitted to the program will have at least a Bachelor's degree in a relevant field. Trainees will enter a via application to the Chemistry department or to a new Chemical Biology Track within the very successful Yale Biological and Biomedical Sciences (BBS) program. Regardless of mode of entry all trainees will share a common first year experience involving interdisciplinary course work, laboratory rotations, as well as close supervision and guidance from the Director of Graduate Students in conjunction with the Executive Committee. At the end of their first year, trainees will chose a thesis advisor and co-mentor from among the CBP trainers and begin intensive research with additional courses in their second year. All students teach for at least one year to aid in their training as teacher-scholars. Programs for increasing the number of minority trainees and for providing education in ethical issues related to research represent important parts of this training program. It is expected that trainees will require 5 to 6 years to complete their training toward the Ph.D. Special features of the training program include interdepartmental course work, including specially designed courses for the new trainees, a rigorous interdepartmental rotation schedule during which the trainee will experience science in three laboratories at Yale, a Fall Chemical Biology Program Retreat, a monthly in-house seminar program for discussion of recent results and an annual Chemical Biology Symposium.